/*
#include <math.h>
#include <algorithm>
#include <string>
#include <map>
#include <hash_map>
#include <set>
#include <vector>
#include <Stack>
#include <iostream>
#include <sstream>
using namespace std;
void combineChild(vector<vector<int>>&result,vector<int>pre,int n,int k,int index){
	if(k==0){
		result.push_back(pre);
	}
	for(int i=index;i<=n;i++){
		pre.push_back(i);
		combineChild(result,pre,n,k-1,i+1);
		pre.pop_back();
	}
}
vector<vector<int>> combine(int n, int k) {
	vector<vector<int>>result;
	vector<int>pre;
	combineChild(result,pre,n,k,1);
	return result;
}
int main(){
	int a[]={2,2,2,0};
	vector<int>data(a,a+sizeof(a)/sizeof(int));
	combine(5,3);
	cout<<endl;
	system("pause");
}
*/